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H U M A N B O D Y : A N O R I E N T A T I O N

Chapter 1 1

Anatomy

 The study of the structure and shape of the body and body parts and their relationships to one another.

 Is static and can be studied on dead specimens during a dissection.

 Uses directional and observational terms to describe what is seen.

 Measures shapes, sizes and weights.

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Physiology

 The study of how the body and its parts work or function.

 Is dynamic and can be studied through experiments and uses the principles of chemistry and physics.

 Often studied on living subjects, for example the digestion of food or the beating of a heart.

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Levels of Structural Organization

 Atoms-The simplest level of organization or the chemical level.

 Cells-The smallest unit of living things.

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 Tissues-Collections of cells with a common function.

 Organs-Composed of two or more tissue types.

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  Organ Systems-A group of organs that work together to accomplish a common purpose.

  Organism-The living body

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Organ System Overview 7

Integumentary System

  The external covering of the body or the skin.

  Waterproofs and cushions the body.

  Protects underlying organs from drying out and mechanical damage.

  Common damage to the skin include cuts and sunburn.

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Skeletal System

 Consists of bones, cartilage, ligaments and joints.

 Supports the body and provides a framework for skeletal muscles to attach.

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Muscular System

 Muscles contract or shorten to provide movement.

 Maintains posture and produces heat.

 Moves limbs.  Allows facial

expression.

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Nervous System

 Fast acting control system.

 Responds to internal and external changes in the body.

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Endocrine System

  Glands secrete hormones that regulate processes such as growth, reproduction and nutrient use.

  Controls the body with chemicals called hormones.

  Glands include the thyroid, ovaries, testes, pituitary, adrenal and pancreas.

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Cardiovascular System

 Heart pumps blood throughout the body in blood vessels.

 Blood vessels transport blood to the body tissues which carries oxygen, carbon dioxide, nutrients and wastes.

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Lymphatic System

 Picks up fluid leaked from blood vessels and returns it to the blood.

 Houses white blood cells involved in immunity.

 Destroys bacteria and tumor cells.

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Respiratory System

 Keeps blood constantly supplied with oxygen and removes carbon dioxide which occurs in the lungs.

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Digestive System

 Breaks food down into absorbable units that enter the blood for distribution to the body.

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Urinary System

 Eliminates nitrogenous wastes from the body and regulates water.

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Male Reproductive System

 To produce offspring.

 Testes produce sperm and male sex hormones.

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Female Reproductive System

  Ovaries produce eggs and female sex hormones.

  Structures provide sites for fertilization and development.

  Mammary glands produce milk to nourish the newborn.

  Provides for conception and childbearing.

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Maintaining Life 20

Maintenance of Boundaries

 Keeps the body’s internal environment distinct from the external environment.

 Membranes around organs as well as the skin.

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Movement

  Includes all the activities promoted by the muscular system.

  Walking, throwing or riding a bicycle.

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Responsiveness

 Ability to react to stimuli.

 Major role of the nervous system.

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Digestion

 Food ingested is broken down to its chemical building blocks.

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Metabolism

 All chemical reactions that occur within body cells.

 Breaks down complex molecules into smaller ones and makes larger molecules from smaller ones.

 Uses nutrients and oxygen to produce ATP.  Regulated by hormones secreted by the

glands of the endocrine system.

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Excretion

 Elimination of carbon dioxide by the lungs and elimination of nitrogenous wastes by the kidneys.

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Reproduction

 Provides new cells for growth and repair.

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Growth

  Increase the number of cells faster than they are destroyed.

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Survival Needs 29

Nutrients

 Taken in via the diet and contain chemicals used for energy and cell building.

 Carbohydrates, proteins and fats are sources of nutrients

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Water

 60-80% of the body’s weight.  Provides the fluid base for body secretions

and excretions.

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Oxygen

 Oxygen is necessary to release energy from chemical reactions that take place in the body.

 Needed to release energy from food.  20% of the air we breathe is oxygen  Oxygen is made available to the body

through efforts of the respiratory and cardiovascular systems.

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Body Temperature

 The body must remain at 37°C (98°F).  If the temperature is too low, metabolic

activities slow down.  If the temperature is too high, chemical

reactions proceed too quickly or proteins begin to break down or become nonfunctional.

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Atmospheric Pressure

 Breathing depends on the pressure exerted on the body.

 If the altitude is too high (lower pressure) gas exchange may be to low to support metabolic activity.

 Mountain climbers need to bring oxygen tanks because oxygen is needed to support metabolic activities.

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Homeostasis

 The tendency of the body’s systems to maintain a relatively constant or balanced internal environment.

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Homeostatic Control Mechanisms

 Communication between organ systems is essential.

 The nervous and endocrine systems are chiefly responsible through chemical or electrical responses.

 Require a receptor, a control center and an effector.

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Receptor

 A sensor that monitors changes in the environment called stimuli.

 Message is sent to the control center along the afferent pathway.

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Control Center

 Analyzes the information from the receptor and determines the appropriate response.

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Effector

 Control center determines the response and activates the effector.

 Provides the means for the control centers response to the stimulus along the efferent pathway.

 The effector is usually a muscle.

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**This occurs between the muscular and nervous system

Negative Feedback Mechanism

 The net effect of the response to the stimulus is to shut off the original stimulus or reduce its effects.

 Example-body releases insulin when sugar is ingested.

 Most common feedback system in the body.

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Positive Feedback Mechanisms

 Increases or enhances the original stimulus.  Examples are blood clotting or the birth of a

baby.

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Language of Anatomy 43

Anterior (Front) 44

Posterior (Back) 45

Medial and Lateral 46

2 Legs vs. 4 Legs Planes of the Body

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Body Cavities 52

Dorsal Body Cavities

 Cranial Cavity contains the brain inside of a bony skull.

  Spinal Cavity contains the spinal cord protected by vertebrae.

 Both dorsal cavities are surrounded by bone to protect the internal structures.

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Ventral Body Cavities

  Thoracic cavity contains the heart and lungs protected by the ribs.

  Abdominal cavity (abdominopelvic) contains the stomach, liver and intestines.

  The thoracic and abdominal cavities are separated by a muscle called the diaphragm.

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